1. Field of the Invention
The present invention relates to fluid coupling having a fixing mechanism which fixes a pipe inserted in a cylindrical coupling body by retreating a sleeve slidably mounted on the body, and more particularly, to a fluid coupling capable of fixing the sleeve in a retreated position, thereby preventing the pipe from slipping out of the fluid coupling.
2. Description of the Related Art
Fluid couplings are conventionally manufactured and used to connect pipes. Many of them are constructed so that a pipe can be fixed to a cylindrical body by operating a sleeve fitted on the body. In order to maintain the connection or the fixed state of the pipe, the fluid couplings of this type require use of fixing means for preventing the sleeve from moving in this state. Generally, in these fluid couplings, the sleeve is designed so as to move straight on the cylindrical body, in the axial direction thereof, so that it cannot be easily fixed. Most of conventional sleeve fixing means utilizes the resilience of a spring for the fixation.
According to the prior art fluid couplings described above, the sleeve can be duly fixed. If it is subjected to any external force greater than the resilient force of the fixing spring, however, the sleeve may possibly move against the urging force of the spring, thereby allowing the pipe to be disengaged therefrom and slip out of the cylindrical body. Thus, these fluid couplings are not suited for applications in which disengagement of the pipe involves a danger. In order to fix the sleeve more securely without using the spring, moreover, the construction of the fluid couplings must be so complicated that it requires troublesome operations. Thus, the conventional fluid couplings cannot enjoy a high operating efficiency, and their manufacture is a hard task, entailing high costs.